The present teachings are related to mass spectrometers and methods for performing mass spectroscopy, and particularly to ion reaction devices for use in mass spectroscopy that can provide simultaneous trapping of positive and negative ions.
Mass spectrometry is an analytical technique for determining the elemental molecules of test samples that has both quantitative and qualitative applications. For example, mass spectroscopy can be employed to identify unknown compounds, determine the composition of elements in a molecule, and determine the structure of a molecule by observing its fragmentation, as well as for quantifying the amount of a particular compound in a sample.
Ion-ion reactions are widely employed in mass spectroscopy. Some examples of such ion-ion reactions include electron transfer dissociation (ETD) of peptide/protein cations via reaction with reagent anions. ETD allows preferential backbone dissociation of protonated peptides/proteins without loss of translational modification. Proton transfer reaction (PTR) is another example of an ion-ion reaction, which can be employed to reduce the charge state of multiply protonated peptides/proteins without causing backbone dissociation. Conventional mass spectrometers in which ion-ion reactions are employed to generate product ions can have certain shortcomings. For example, the way by which the precursor and reagent ions are conventionally introduced into a mass spectrometer can lead to a reduction of duty cycle.
There is a need for enhanced systems and methods for introducing positive and negative ions (e.g., precursor cations and reagent anions) into a mass spectrometer.